Transmitter



May 16, 1933. w. BUSCHBECK TRANSMITTER Filed Feb. 29, 1952 INVENTORWERNER BUSCHBE BY 5 ATTORNEY Patented May 16, 1933 UNITED STATESFATZEN'T @FFEQE.

SCI-IAFT FUR DR-AHTLOSFZ PORA'IION OF GERMANY TELEGRAa -1 IE 11E. B.H... 035 BERLIN, GERMANY, A COR- TRANSMITTER Application filed February29, 1932, Serial No. 595,893, and. in Germany Ianuary 9, 1931.

This invention relates to a circuit arrangement adapted. to reducehigh-frequency energy losses in plate protective resistances inpush-pull transmitters.

The invention will be described by reference to the attached drawingthroughout which like reference numerals indicate like parts and inwhich, Fig. 1 shows a trans mitting circuit in which the novel featuresof the present invention are included; while Figs. 2, 3 and 4 showmodifications of the arrangement of Fig. 1.

It is known from the practical use of water-cooled tubes that inter-tubeflashovers are occasionally produced whenever the plate potential ishigh. In order that the tube may escape damage upon the arising of suchfiashover it is necessary to provide means and ways intended to limitthe current in the flashover, and this end may be insured by the aid ofprotective resistances included in the plate circuit. Across theseresistances naturally a direct current fall of potential and as a resultdirect our- 4 rent losses are caused. Losses in radio frequency energymay be diminished to a harmless level by shunting the radio frequencyenergy around the protective resistances. Thus in a well known mannerthe radio frequency current flowing by way of the radio frequencychoke-coil D (Fig. l) is drained by way of the condenser C2 or byseries-connection of C1 and C3 to the filament without passing theresistance. In this scheme C1 shunting the source S must mostly be highcompared with C2 and C3.

Such shunting. however. is on the other hand undesirable when it isdesired to suppress certain disturbing waves which flow through thedirect current electromotive force since in the absence of the radiofrequency shunts or lay-passes the plate protection resistances lieinside the said circuit carrying troublesome waves so that the latterare suppressed. In a circuit scheme of the kind shown in Fig. 1 it is,however, not feasible to entirely prevent radio frequency energy lossesin the plate protective resistances without radio frecniency shunting.

An arrangement similar to the scheme rent source S around the protectiveresistances are shunted or bridged. This inconvenience according to theinvention may be avoided and at the same time means may be provided forshunting or by-passing the fundamental wave around the resistances byconnecting the middle of the two condensers G2 which in this case becombined into a single unit together and disconnecting them from thefilament as shown in Fig. 3. What is furtherohtained by this arrangementis a reduction in cost of the condensers C2 inasmuch as these willno'longer carry any direct current under normal working conditions. Thisis not true of the scheme shown in Fig. 2 where the condensers C2 arecon stantly connected all the time with the full directcurrent-potential. 'In fact, these con densers should be designed merelyfor a test potential equal to the plate direct current potential sincethis potential would arise across the terminals thereof in case of atube flashover.

When using a plurality of paralleled tubes for each sideof thetransmitter, the chokecoils of pairs of opposite tubes are embraced byone condenser as shown in Fig. 4. In the arrangement. of Fig. l theterminals of each choke'coil D remote from the plate electrode of thetube to which it supplies charging potential is connected as shown tothe corresponding terminal of another tube similarly located in groupsof push-pull tubes through a condenser C2 as indicated. This perm. s theradio frequency currents to pass .hrough the circuits without passinthrough the resistances 9", wherein losses would occur. At the same timethe condensers C not being connected to the filaments of the tubes arecated in Fig. 1. The same is true of the electrodes of the tubes V, V1of the symmetrical arrangements of Figs. 2, 3 or i.

The tank circuit of each modification ma be connected with any loadcircuit, for example, an aerial system as indicated in Fig. 1 or anamplifier as indicated in Fig. 3.

Having now described the natrre off my invention and the operationthereof 1 claim as novel:

1. An alternatin current -relay including, a pair or" hermionic tubes,each having an anode and a cathode, the cathodes being connectedtogether, an alternating current circuit there bein connecting theanodes of said tubes in pushpull relation, said alternating currentcircuit being completed by a direct connection to the cathodes of tubes,a source of direct current potential, a separate circuit for applyingdirect current potential between the anodes and cathodes of said tubescomprising, a connection between one terminal of said source and thecathodes of said tubes, connections between the other terminal of saidsource and the anode electrode of each of said tubes, a resistance and achoke coil in series in each of said connections in the order given, theresistance acting to prevent flashover between said tubes when theapplied direct current potential is too high, the choke coil acting tosubstantially prevent alternatcurrent from said alternating currentcircuit from reaching said resistance in said direct current source, andmeans for shunting any alternating current which gets through said chokecoils around said source and said resistance including a capacityconnecting the adjacent terminals of the resistance and choke coil inone of said connections to the adjacent terminals of the resistanceandchoke coils in the other of said connections.

'2. A radio frequency relay including, a pair or thermionic tubes, eachhaving an anode and acathode, the cathodes being connected together, analternating current circuit including an inductance connecting theanodes of said tubes in push-pull relation, a pair of capacities inparallel with said inductance, and means for completing said alternatingcurrent circuit including, a connection between adjacent electrodes ofsaid capacities and the cathodes of said tubes, a

source of direct current potential, and means for applying potentialfrom said source between the anode and cathode of each of said tubesincluding, a connection between a negative terminal or said directcurrent source and the cathodes of said'tubes, a resistance and aninductance in series in the order given connecting the positive terminalof said source to the anode of one of said tubes, a second resistanceand a second inductance in series in the order given connecting thepositive terminal of said source to the anode of the other of saidtubes, the purpose of said resaid second named resistance and saidsecond named inductance, and a capacity connected in parallel with saidsource.

3. An arrangement as recited in claim 1 in which there are a pluralityof pairs of tubes, each pair having its anode circuit connected inpush-pull relation byan alternating current circuit, as set forth inclaim 1, and in which each pair of tubes has its anode electrodesconnected to said direct current source by direct current energizingcircuits, as recited in claim 1.

a. An arrangement as recited in claim 2 in which there are a pluralityof pairs of tubes, each pair having its anode electrodes connected inpush-pull relation with the same alternatingcurrent circuit, and inwhich each pair of tubes has its anode electrodes connected to saiddirect current source by direct current energizing circuits, as recitedin claim 2.

WERNER BUSCHBECK.

